This article is chiefly about the present-day route; for historical development of the West Highland Railway (Company) see West Highland Railway

The West Highland Line (Scottish Gaelic: Rathad Iarainn nan Eilean - "Iron Road to the Isles") is a railway line linking the ports of Mallaig and Oban in the Scottish Highlands to Glasgow in Central Scotland. The line was voted the top rail journey in the world by readers of independent travel magazine Wanderlust in 2009, ahead of the iconic Trans-Siberian line in Russia and the Cuzco to Machu Picchu line in Peru.[2][3][4] The ScotRail website has since reported that the line has been voted the most scenic railway line in the world for the second year running.[citation needed]

During the summer season from May until October a steam locomotive-hauled daily return service between Fort William and Mallaig known as "The Jacobite" is operated by West Coast Railways. There is usually one train a day but this is increased to two trains from June until the end of August.

The West Highland Line is one of two railway lines which access the remote and mountainous west coast of Scotland, the other being the Kyle of Lochalsh Line which connects Inverness with Kyle of Lochalsh. The line is the westernmost railway line in Great Britain.

At least in part, the West Highland Line is the same railway line as that referred to as the West Highland Railway.

Shortly after leaving Queen Street station in Glasgow, and beyond Queen Street Tunnel, the line diverges from the main trunk route to Edinburgh & Perth at Cowlairs and follows a northwesterly course through the suburbs of Maryhill and Kelvindale. Between Westerton and Dumbarton, the route is shared with the North Clyde Line to Helensburgh before branching northward at Craigendoran Junction towards Garelochhead, the section where the West Highland Line itself is generally accepted to begin. It gives high-level views of the Gareloch and Loch Long before emerging alongside the northwesterly shores of Loch Lomond, then climbs Glen Falloch. Significant points on the journey include Crianlarich, an important Highland junction of both road and rail, and Tyndrum, the smallest place in Scotland, and the northernmost place in Britain, with two railway stations.

After Bridge of Orchy, the line climbs onto Rannoch Moor, past the former crossing point at Gorton Crossing to Rannoch station. In winter, the moor is often covered with snow, and deer may be seen running from the approaching train. The station at Corrour on the moor is one of the most remote stations in Britain and is not accessible by any public road. This is the summit of the line at 410 m (1347 ft) above sea level. Carrying on northwards, the line descends above the shores of Loch Treig and through the narrow Monessie Gorge. The final stop before Fort William is Spean Bridge. The section between Fort William and Mallaig passes over the Glenfinnan Viaduct, through Arisaig with its views of the Small Isles of Rùm, Eigg, Muck and Canna, and the white sands of Morar before coming to Mallaig itself.

The branch to Oban diverges at Crianlarich, and runs through Glen Lochy to Dalmally and through the Pass of Brander to reach salt water at Taynuilt and Connel Ferry before a final climb over a hill to Oban.

Since improvements to Scottish trunk roads in the 1980s, a train journey can take significantly longer than the equivalent road journey. There are several reasons for this. The line is entirely single track once it leaves the North Clyde suburban network at Craigendoran and trains must wait at stations with crossing loops for opposite direction trains to pass. Even when no crossing is timetabled, each train must pause at the various token exchange points whilst the driver contacts the main signalling centre at Banavie to swap tokens electronically and obtain permission to proceed. Up to 15 minutes have to be allocated for trains to divide or combine at the junction station at Crianlarich, whilst trains heading to/from Mallaig also have to reverse at Fort William & traverse the Banavie swing bridge at low speed. A further issue is finding suitable timetable paths for Oban & Mallaig trains on the busy North Clyde line, which carries an intensive local stopping service. As West Highland trains only stop at Dumbarton Central & Dalmuir on this stretch, it is not uncommon for them be delayed by a preceding local train and so recovery time has to be included in their schedules to reduce the possibility of a late arrival in Glasgow.

Over much of the Rannoch Moor section the speed limit is 60 mph for the Sprinter and 70 mph on the approach to Rannoch station. The Caledonian Sleeper travels at 40 mph maximum, slowing down for a number of bridges on the route due to the heavy weight of the Class 67 locomotive which hauled the train until the end of the old franchise in April 2015. New sleeper operator Serco has replaced these with refurbished Class 73/9 electro-diesels since it took over, which have a lighter axle load; it isn't yet clear if the new locos will be cleared to run at higher speeds now they are in service.[5]

Places served along the route from Glasgow Queen Street are listed below. Sleeper services to Fort William start, however, at London Euston, calling at Edinburgh Waverley and Queen Street Low Level (to pick up or set down depending on direction).